Resolving dependencies...
cabal: Could not resolve dependencies:
next goal: vacuum (user goal)
rejecting: vacuum-2.2.0.0, 2.1.0.1, 2.1.0.0, 2.0.0.0, 1.0.0.2, 1.0.0.1, 1.0.0,
0.0.95, 0.0.94, 0.0.93, 0.0.92, 0.0.91, 0.0.9, 0.0.8, 0.0.7, 0.0.6, 0.0.5.1,
0.0.5, 0.0.4, 0.0.3, 0.0.2 (global constraint requires ==0.0.1)
trying: vacuum-0.0.1
next goal: ghc (dependency of vacuum-0.0.1)
rejecting: ghc-7.10.2/installed-a64... (conflict: vacuum => ghc==6.10.1)
Dependency tree exhaustively searched.